1. Field of Invention
This invention relates to triangular-shaped, retrofit, gusset connectors that permanently attach intersecting structural members to make a building resistant to wind and earthquakes.
2. Prior Art
During an earthquake, the floor, wall, and roof diaphragms undergo shearing and bending. The outside sheathing provides lateral stability to the walls, preventing racking. The sheathing also absorbs and transfers earthquake forces by becoming a shear wall. This invention helps prevent the wall studs from moving, thus helping prevent the outside sheathing from pulling away from the wall during earth movements.
Steel connectors, between different components of a wood-frame building's superstructure, provide continuity so that the building will move as a unit in response to seismic activity. This invention ties the walls securely together and to the foundation, so the house will move as one unit.
Previous steel connectors used a right angle bend to brace intersecting structural members. Some used multiple bends. Some used a triangle, which is known to be strong in multiple angles. Some had to be attached to two or three sides of a structural member to provide bracing and strength. This invention can be installed on just one side of each structural member to provide great strength to the connection. This connector uses multiple triangles, and bends. It also forms multiple triangles when it is fastened to intersecting structural members.
Recent studies of hurricane damage on wood-frame buildings indicate that extensive damage was generated to a house by strong winds, when the walls moved away from the foundation, and adjacent walls moved away from each other. This invention helps prevent the wall sheathing from detaching from the wall during strong winds, by preventing the wall from bending, twisting, and moving.
Triangular gussets have been around since the middle ages where they were used to reinforce areas of clothing. Triangular gussets are still used to reinforce under the arms of suits, in the crotch of certain pants, and in the heels of socks.
Triangular wood gussets have been used in furniture-making to reinforce wood legs to the table top. Triangular metal gussets have been used to reinforce motorcycle frames, and as motor mounts and suspension frames in automobiles. Most of these triangular gussets were single triangles.
Where two triangles have been used, they are usually spaced apart. Grizzly Inc. has a cast-iron slotted angle plate (G9577), consisting of a right angle bracket with a triangular gusset at either end.
A gusset is defined as a plate or bracket for strengthening an angle in framework. The Simpson Strong-Tie Company, a leading manufacturer of construction connectors, has several gussets listed in their 2009-2010 catalog. They have many connectors with right angles, but only a few with triangles. Page 134 shows a TBE, Truss Bearing Enhancer, that has two triangular gussets on either end of a plate.
Simpson's page 138 shows a GBC, Gable Brace Connector, that has a broad gusset pushed up in the center of the bend between the horizontal and vertical members. Page 143 shows a HGAM10, Hurricane Tie, that also has a broad gusset pushed up in the center of the bend between the horizontal and vertical members.
Simpson's page 169 shows a SBV/CF-R, Shelf Brackets/Concrete Form Angles, that consist of triangles with tabs on two sides. Page 180 shows an HL, Heavy Angles & Gussets, that consists of an angle iron with an optional triangular gusset in the middle.
Inoue's torsion-beam suspension, U.S. Pat. No. 7,284,765, uses a triangular gusset on his suspension. McCraney's water heater restraint, U.S. Pat. No. 5,487,518, uses triangles to help hold a cylindrical water heater. Wood's flexible side gusset square bottom bags, U.S. Pat. No. 5,165,799, uses connected triangles to make a flexible bag. Box's heavy-duty full-depth beverage case, U.S. Pat. No. 4,548,320 uses molded ribs to form triangles as gussets. Fleishman's interconnecting members for enclosures, U.S. Pat. No. 4,308,698, uses gussets and struts to form triangles for a geodesic dome. Pritchart's corner gusset, U.S. Pat. No. 4,127,347, uses a triangular gusset between mitered corners.